AIT Pipefitter Level 3 Practice Test 2026 - Free Pipefitter Practice Questions and Study Guide

Thermal treatment in water treatment refers to processes that involve the application of heat to modify water properties, particularly in removing contaminants or improving quality. De-aeration is a thermal treatment method where water is heated, which helps to remove dissolved gases such as oxygen and carbon dioxide. This process is crucial because extraneous gases can cause problems in water systems, such as corrosion or decreased efficiency in chemical treatments.

In contrast, clarifiers are primarily physical devices used to settle out solids from the water. Filters operate by removing particulates and larger contaminants through physical barriers. Reverse osmosis is a membrane filtration process that separates smaller contaminants from water, but it does not typically involve thermal processes. Hence, de-aeration is the correct example of thermal treatment among the options provided, as it relies on heat to achieve its purpose.